A HVAC system can include a chiller, which typically includes a compressor, an evaporator, and a condenser forming a refrigeration loop. Typically, the compressor is configured to compress a refrigerant vapor; the condenser is configured to condense the compressed refrigerant vapor to a liquid refrigerant; and the evaporator is configured to utilize the liquid refrigerant to cool a process fluid, such as water. In some embodiments, the compressor may be configured to have two or more compression stages.
Some HVAC systems may include an economizer, which is typically positioned between the condenser and the evaporator in the refrigerant loop. The economizer may improve an operational efficiency of the HVAC system by flash cooling the liquid refrigerant from the condenser to a temperature that may be lower than the temperature of the liquid refrigerant leaving the condenser. It is known in the art that the economizer may vaporize a portion of the liquid refrigerant from the condenser (also known as flash refrigerant) to provide flash cooling. The vaporized flash refrigerant from the economizer may be directed back to the compressor for compression.